This invention relates to an improved process for preparing hydroxy ethyl p-(.beta.hydroxyethoxy) benzoate. More particularly, this process involves the reaction of p-hydroxybenzoic acid with ethylene carbonate to prepare the title compound.
The reaction of ethylene carbonate with phenol or phenolic compounds in the presence of a cesium or potassium iodide catalyst to prepare hydroxyalkylphenyl ether compounds is disclosed in U.S. Pat. No. 4,261,922. The use of acid or base catalysts for such reactions is described in U.S. Pat. Nos. 2,448,767 and 3,283,030.
British Pat. No. 742,793 discloses that methyl esters of p-hydroxybenzoate can be reacted with cyclic ethylene carbonate to prepare a linear polyester. In the provisional specification of this application, it is noted that cyclic glycol carbonates react readily with free dicarboxylic acids. Diglycol esters are acid of 3:1 or higher. formed at mole ratios of cyclic carbonate to dicarboxylic
Japanese Pat. No. 75 16,839 (Chem. Abst. 83:180287u) describes the preparation of hydroxy ethyl p-(.beta.hydroxyethoxy) benzoate by the reaction of p-hydroxybenzoic acid and ethylene oxide. However, this reaction is prone to the formation of poly(ethoxy) groups in the product and is not easily adapted to commercial operations.
The object of the subject process is to provide an improved method of making hydroxy ethyl p-(.beta.hydroxyethoxy) benzoate, hereinafter referred to as "HEHEB". HEHEB is useful as a monomer for fiber-forming polyesters and also as a chain extender for polyurethanes.